1. Field of the Invention
This invention relates to medical instruments, and more specifically, to a medical instrument for isolating a patient's cervix.
2. Related Art
Currently, therapeutic agents, e.g. misoprostol, are delivered to a human cervix either by inserting a tablet or gel directly into a patient's vagina, which exposes both the vagina and cervix to the agent, or by direct injection of the agent into the cervix with a needle, which can be extremely painful to the patient. The disadvantage with these procedures, however, is that several agents designed for drug therapy to the cervix are either systemically toxic or cause irritation to the vagina or outer vulva. Alternatively, other agents given for cervical maladies are creams which also can be inserted into the vagina. The disadvantage with creams is that they often leak out onto the vulva and become extremely irritating and painful.
Therefore, a cervical agent isolation and delivery apparatus is needed that provides for the direct administration and delivery of therapeutic agents to a patient's cervix, e.g., anesthetics, anti-virals, anti-neoplastics and cervical ripening agents, while minimizing vaginal and systemic exposure to the agent. Since the cervix is not as highly vascularized as the vagina, direct administration to the cervix of a therapeutic agent would reduce systemic exposure of the agent to other areas of the patient since less of the agent would be distributed to the body and the desired organ (cervix) will be specifically targeted.
One example of conventional methods of drug delivery to a patient's cervix involves the administration of anesthetic agents to reduce pain and discomfort prior to cervical dilation or biopsy. Currently, there are no other established methods for administering anesthetic agents to a patient's cervix other than direct injection of the anesthetic via a needle and syringe. Most patient's report this injection to be more painful and uncomfortable than the procedure (which itself is uncomfortable and sometimes painful). Thus, the majority of women, and their physicians, choose to forego the administration of any anesthetic agent and simply endure the pain associated with the procedure itself.
As another example of conventional methods for cervical drug delivery, Misoprostol, a tablet traditionally used to prevent non-steroidal anti-inflammatory drug induced ulcers in a patient's stomach, is sometimes delivered to the cervix. However, Misoprostol is contra-indicated on its label for use with a pregnant patient because of its effect for inducing labor. In reality, however, physicians often apply Misoprostol for its off-label use in the promotion of cervical ripening in pregnancy wherein the physician directly applies a Misoprostol tablet to a patient's cervix in order to induce cervical ripeness, thereby inducing labor. There are many disadvantages with using Misoprostol for this off-label use. First, this topical use is directly counter to the drug's allowed use. Second, the tablet form of Misoprostol is intended for oral ingestion only—not as a topical agent. Therefore, the tablet form occasionally does not dissolve in a vagina. In addition the tablet may be difficult to position properly so as to directly contact the cervix. Lastly and most importantly, the proper dosage of Misoprostol has not been ascertained or even studied because this use of Misoprostol is a non-labeled use. Therefore, physicians typically use a “hit or miss” dosage until the desired effect is achieved.
Another type of device used in connection with covering a patient's cervix is the cervical cap. For example, the Prentif Cervical Cap® covers a patient's cervix and is used as a barrier method of contraception. Similarly, the Today® contraceptive sponge is a sponge-like device shaped to fit over a patient's cervix, thereby also serving as a physical contraceptive barrier. However, the Today® sponge also contains nonoxynol-9 (a spermicidal agent) which is released into the vagina to assist in preventing contraception. A second type of cervical cap is the Instead® (cervical) Cap which is a flexible ring connected to a flexible plastic sac-like reservoir. The ring fits around a patient's cervix wherein the reservoir collects the patient's menstrual flow. This device is not designed to fit closely around the cervix.
Other types of devices used in connection with a patient's cervix consist of a catheter that is inserted through the cervix and into the uterus to allow administration of therapeutic agents to enhance the contrast seen in the uterus during an ultrasound procedure. An example of this type of device is the Zinnanti Uterine Injector® which is a catheter having a cervical stop to prevent inserting it too far into the patient's uterus. This device is available in 2 and 4 mm sizes, and in dual lumen designs allowing delivery of an agent through one lumen and delivery of air to a balloon-like structure through the second lumen to prevent it from coming out of the uterus.
While the various devices and methods are aimed either at isolating or treating a patient's cervix, none provides an effective means to both deliver a medicine to the patient's cervix while simultaneously isolating the cervix from surrounding anatomical structures. There remains a need for a medical instrument that allows a physician to isolate a patient's cervix while administering a treatment thereto.